linux/arch/x86/entry/syscall_32.c
Josh Poimboeuf 9142be9e64 x86/syscall: Mark exit[_group] syscall handlers __noreturn
The direct-call syscall dispatch function doesn't know that the exit()
and exit_group() syscall handlers don't return, so the call sites aren't
optimized accordingly.

Fix that by marking the exit syscall declarations __noreturn.

Fixes the following warnings:

  vmlinux.o: warning: objtool: x64_sys_call+0x2804: __x64_sys_exit() is missing a __noreturn annotation
  vmlinux.o: warning: objtool: ia32_sys_call+0x29b6: __ia32_sys_exit_group() is missing a __noreturn annotation

Fixes: 1e3ad78334 ("x86/syscall: Don't force use of indirect calls for system calls")
Closes: https://lkml.kernel.org/lkml/6dba9b32-db2c-4e6d-9500-7a08852f17a3@paulmck-laptop
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/5d8882bc077d8eadcc7fd1740b56dfb781f12288.1719381528.git.jpoimboe@kernel.org
2024-06-28 15:23:38 +02:00

45 lines
1.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* System call table for i386. */
#include <linux/linkage.h>
#include <linux/sys.h>
#include <linux/cache.h>
#include <linux/syscalls.h>
#include <asm/syscall.h>
#ifdef CONFIG_IA32_EMULATION
#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, compat)
#else
#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
#endif
#define __SYSCALL(nr, sym) extern long __ia32_##sym(const struct pt_regs *);
#define __SYSCALL_NORETURN(nr, sym) extern long __noreturn __ia32_##sym(const struct pt_regs *);
#include <asm/syscalls_32.h>
#undef __SYSCALL
#undef __SYSCALL_NORETURN
#define __SYSCALL_NORETURN __SYSCALL
/*
* The sys_call_table[] is no longer used for system calls, but
* kernel/trace/trace_syscalls.c still wants to know the system
* call address.
*/
#ifdef CONFIG_X86_32
#define __SYSCALL(nr, sym) __ia32_##sym,
const sys_call_ptr_t sys_call_table[] = {
#include <asm/syscalls_32.h>
};
#undef __SYSCALL
#endif
#define __SYSCALL(nr, sym) case nr: return __ia32_##sym(regs);
long ia32_sys_call(const struct pt_regs *regs, unsigned int nr)
{
switch (nr) {
#include <asm/syscalls_32.h>
default: return __ia32_sys_ni_syscall(regs);
}
};